Self-aligning attachment for countersinking apparatus



June 5, 1962 I s. E. REES 3,037,401

SELF-ALIGNING ATTACHMENT FOR COUNTERSINKING APPARATUS Filed April 6, 1959 2 Sheets-Sheet 1 h P A l6 A 25 83 A? ATTORNEY S. E. REES June 5, 1962 SELF-ALIGNING ATTACHMENT FOR COUNTERSINKING APPARATUS 2 Sheets-Sheet 2 Filed April 6, 1959 INVENTOR. \ffiro oJ/fixre E. Re d ATTORNEY Texas Filed Apr. 6, 1959, Ser. No. 894,307 4 Qiairns. (Cl. 77--2) This invention relates generally to a portable apparatus adapted to countersink, counterbore or spotface holes in metal sheet or plate, but more particularly to a self equalizing device adapted to be secured to the front end of such apparatus and intended to maintain the apparatus and its cutting tool in axial alignment with the hole, thereby assuring concentric relationship between the hole and its countersink, coun-terbore or spotface.

One object of this invention is to provide such an apparatus with a self equalizing or leveling attachment enabling the countersinking, counterboring or spotfacing of a hole to be aligned or concentric with the hole regardless of the contour or unevenness of the surface of the sheet or work on which the apparatus is applied.

Another object of this invention is to provide a self equalizing device for the front end of such a tool having work engaging faces radially spaced from the cutting tool and affording purchase to prevent such drift or walking of the cutting tool which may result from unequal cutting of the tool.

Another object of this invention is to provide such an apparatus with a shield surrounding the cutting tool, thereby causing the cutting chips to be retained within a relatively small area on the face of the work.

Another object of this invention is to provide a self aligning attachment especially applicable for use with a countersinking apparatus of the type described in the United States Patent No. 2,669,887 of February 23, 1954.

Other objects and advantages will be further brought out in the following description, wherein:

FIG. 1 is a side elevational view, partly in section of the device embodying the invention.

FIG. 2 is a view similar to FIG. 1 but illustrating parts in different positions.

FIG. 3 is a longitudinal View, partly in section, taken on line 3--3 in FIG. 1.

FIG. 4 is a cross sectional view taken on line 4--4 in FIG. 3 looking in the direction of the arrows.

FIG. 5 is a cross sectional view taken on line 55 in FIG. 3 looking in the direction of the arrows.

The self aligning device about to be described is primarily intended as an attachment for the front end of the countersinking apparatus shown and described in the United States Patent No. 2,669,887 of February 23, 1954, and for better understanding of its function and operation, reference should be made to that patent.

It is to be understood that this invention is restricted to a self equalizing device preferably secured to the front end of an apparatus of the type described in the aforesaid patent, portions of which apparatus are shown in the accompanying drawings only to illustrate a preferred method of attaching the device to the apparatus. Since the apparatus does not form a part of this invention, the portions thereof shown in the drawings will not be described in detail but have been assigned reference numerals corresponding to those used in the patent.

The preferred method of attaching the self equalizing device to the apparatus involves two small changes to be made within the front end portion D of the apparatus, which changes are clearly shown in the accompanying drawings. One change consists of enlarging the opening 8 3 of only one of the three foot pieces 77, and providing this enlarged opening with an internal screw thread 10. A plug 11 is then screwed into the opening -83 to close the lower end of the cylinder 78. This plug is provided with a central bore 12 through which the piston guide rod 32 of the patent is free to slide. The seal 84 of the patent is, in this instance, carried by the plug 11 around the piston rod 82 and an additional seal 13 is provided between the plug 11 and the inner wall of the cylinder 78.

The second change to be made consists of extending one of the three coil spring recesses 87 through the cylindrical shaped body 75 and providing the lower end of this extended recess with internal screw threads 14. A plug 15 is then screwed in this extended recess to close the recess and afford a seat for one end of the coil spring 86. In order for the self equalizing device about to be described to perform adequately, it is important that the one of the three spring recesses 87, which is to be changed as above described, be diametrically opposed to the one of the three cylinders 78 equipped with the plug 11 above described.

Referring now more particularly to the invention, the plug 11 has a nipple 16 screwed therein and provided with a central cylindrical recess 17 affording clearance for the piston guide rod 82. This nipple is formed with the usual hexagonal head 18 from which extends a lug 19 of rectangular cross section. The plug 15 is provided with a cylindrical head 20 from which extends a lug 21 equivalent in size and shape to the lug 19. The lugs 19 and 21 alford supporting means for the self equalizing device, which comprises a first ring like member 22 surrounding the rotary cutting tool A which projects from the front end of the apparatus. This first ring is laterally spaced from. the cutter A and is provided with two diametrically opposed elongated slots 23 and 24 (FIG. 5), in which are loosely fitted the lugs 19 and 21 respectively, which lugs are connected to the first ring by a cross pin 25 carried by the lug 19 and extending radially through the body of the ring, and a second coaxial cross pin 26 carried by the lug 21 and extending similarly through the ring 22. Thus it will be understood that the first ring 22 is mounted on the front end of the countersinking apparatus for pivotal movement on an axis 28 which is perpendicular to the longitudinal center axis of the apparatus. In order to normally maintain the upper ring 22 perpendicular to the longitudinal central axis of the countersinking apparatus, the side of the ring adjacent to the front end of the apparatus is provided with two cylindrical recesses 29 located one on each side and equidistant from the pivotal axis 28 and each accommodating a compression spring 30' which projects therefrom against the front end of the apparatus. Fixed to the interior of the ring '22 by solder or the like, is a shield in the form of a sleeve 31 which is flush with the right face of the ring but projects beyond the left face thereof a predetermined extent. As clearly shown in FIG. 1 this cylindrical shield is laterally spaced from the cutting tool A. In addition to the slots 23 and 24 the ring 22 is provided with two similar slots 32 and 33 which extend through the ring and are located at right angles from the slots 23 and 24.

Patented June 5, 1962 A second ring 34 is located to the left of the first ring in coaxial alignment therewith. This second ring is provided with two lugs 35 and 36 of rectangular cross section which projects into the slots 32 and 33 respectively of the first ring 22 where they are pivotally connected thereto by two coaxial pins 37 and 38 which pins extend radially through the first ring and the lugs 35 and 36. Thus it will be understood that the second ring 34 is connected to the first ring 22 for pivotal movement on an axis 40 perpendicular to the axis 28 and located Within the same perpendicular plane relative to the longitudinal central axis of the countersinking apparatus. In order to normally maintain the two rings 22 and 34 substantially parallel, the face of the first ring 22 adjacent to the second ring 34 is provided with four cylindrical recesses 41 each accommodating a compression spring 42 which engages the adjacent face of the second ring 34, thus the springs 42 tend to maintain the ring 34 parallel to the ring 22 and also prevent free pivotal movement of the ring 34 on its axis 40. The face of the second ring 34 remote from the ring 22 is provided with three raised foot pads 43 which project slightly from that face of the ring, and are equally spaced and intended to engage the work during operation of the countersinking apparatus. Preferably these foot pads extend radially to the outer edge of the ring. The inner diameter of the second ring 34 is substantially larger than the outside diameter of the cylindrical shield 31, thereby enabling pivotal movement of the second ring relative to the first ring without interference from the shield 31, which shield extends through the second ring but ends short of the raised foot pads 43.

When the self equalizing device above described is attached to the front end of the countersinking apparatus in the manner above set forth, and the apparatus is applied to a work piece such as a metal sheet or plate having a hole therethrough which the apparatus is to countersink, counterbore or spotface, it will be understood that since the work contacting ring 34 is adapted to pivot on two cross axes 28 and 49, the apparatus can readily be maintained in axial alignment with the hole to be countersunk, counterbored or spotted. As illustrated in FIGS. 1 and 2, in the event the face of the Work is not perpendicular to the axis of the hole, the self equalizing device will first engage the work in the manner shown in FIG. 1, with the rings 22 and 34 gradually pivoting on the pivot axes Z8 and 40 as the countersinking operation takes place to assume the position in FIG. 2 at the conclusion of the countersinking operation. In other words, by providing the front end of the countersinking apparatus with a work engaging device adapted to swivel on two axes perpendicular to each other, the apparatus can readily be maintained in axial alignment with the hole to be countersunk without interference from the front end of the apparatus engaging an uneven or non-perpendicular surface of the work piece. Since in the type of apparatus described in the aforesaid patent for which this self equalizing device is intended as an attachment, it is necessary for a portion of the apparatus, generally the front end thereof, to engage the surface of the work in order to control the rate of penetration of the cutting tool as well as the depth of the cut by mechanisms provided for that purpose. It has been found that when using the apparatus on an uneven or a non-perpendicular surface relative to the axis of the hole to be countersunk, the apparatus, unless equipped with the self equalizing device above described, had the tendency to be cocked away from axial alignment with the axis of the hole, thereby resulting in an eccentric relationship between the hole and the countersink.

The three foot pads 43 provided on the face of the ring 34 adjacent to the work piece, offer three points of engagement of the front end of the apparatus with the work and further provide purchase to prevent such drift or Walking of the cutting tool which may result from unequal cutting action of the tool on an uneven surface.

In practice, the length of the shield 31 is such as to cause the free end of the shield to be located close to the surface of the work, thereby isolating the self aligning device from the cutting chips, grime and the like incidental to the cutting operation, as well as causing the cutting chips to be retained within a relatively small area on the surface of the work, from which they can readily be removed after the removal of the apparatus from the work.

Although the foregoing description is necessarily of a detailed character in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining, and it is to be further understood that various rearrangement of parts and modifications of structural details may be resorted to without departing from the scope or spirit of the invention as claimed.

I claim:

1. A self aligning attachment for a countersinking apparatus and the like including a housing having a rotary cutting tool mounted thereon, comprising a first member and a second member surrounding said tool in coaxial relationship therewith, said first member connected to said housing for pivotal movement on a first axis, means connecting said second member to said first member for pivotal movement on a second axis perpendicular to said first axis, said first and second axes located with a single plane perpendicular to the longitudinal center axis of said tool, work contacting means on said second member, and a sleeve like shield surrounding said tool carried by said first member and extending therefrom through said second member, said shield being externally spaced from said tool and internally spaced from said second member.

2. A self-aligning attachment for a countersinking apparatus including a housing having a rotary cutting tool mounted on the lower portion thereof, comprising a first ring-like member surrounding said tool in spaced relationship therewith, means connecting said first ring to said housing for pivotal movement on a first axis perpendicular to the longitudinal center axis of said tool, a work engaging second ring-like member disposed in coaxial relationship with said tool and axially spaced from said first ring, means connecting said second ring to said first ring for pivotal movement on a second axis perpendicular to said first axis, said first and second means spaced an equal distance from the longitudinal center axis of said tool.

3. A self-aligning attachment for a countersinking apparatus and the like including a housing having a rotary cutting tool mounted on the lower portion thereof, comprising a first member and a second member disposed in spaced planar relation with one another along the median axis of said tool, said members surrounding said tool in spaced and coaxial relationship therewith, said first member connected to the lower end of said housing for pivotal movement on a first axis, means connecting said second member to said first member on a second axis perpendicular to said first axis with said second member being spaced from said first member, said first and second axis located within a single plane perpendicular to the median axis of said tool, means interposed between said members normally maintaining said members parallel to said plane and work contacting means on said second member.

4. A self-aligning attachment for a countersinking apparatus and the like including a housing having a rotary cutting tool mounted on the lower portion thereof, comprising a first member and a second member disposed in spaced planar relation with one another along the median axis of said tool, said members surrounding said tool in spaced and coaxial relationship therewith, said first member having a plurality of diametrically disposed openings therein, a pair of spaced lugs on the lower portion of said housing projecting through a pair of the openings in said first member, means carried by said first member engaging said lugs for pivotally connecting said first member to said housing on a first axis, said second member having a pair of diametrically spaced projections thereon arranged to project through a pair of openings in said References Cited in the file of this patent first member, means carried by said first member engaging UNITED STATES PATENTS said pro ections for prvotally connectmg said second member to said first member on a second axis perpendicular to 2,278,314 Houchm 31, 1942 said first axis, said means and lugs and projections located 5 2,372,088 KaVenY 20, 1945 within a single plane perpendicular to the median axis of 2,381,102 Boyfi 1945 said tool, and resilient means interposed between said 2,383,854 Gwlnn et a1 1945 2,527,968 Sherman et a1 Oct. 31, 1950 first member and housing and between said first member and second member normally maintaining said members 2,669,887 Rees Feb. 23, 1954 parallel to said plane. 10 2,787,866 Gross Apr. 9, 1957 

